... 4.High precision,durability Company IntroductionYongcheng Group, is a large copper sets of domestic manufacturers, one specializing in the production of ... of products: 1. Crusher bearings series 2. Copper vulcanizer sets series 3. Self-lubricating bearings Series 4.Punch series 5 ... .Others: aluminum castings, zinc-based alloy sets, copper bushings, sleeve, copper, brass bronze plate